Rim for mounting tubeless tires, particularly for bicycles, motorcycles and mopeds

ABSTRACT

A rim for mounting tubeless tires, particularly for bicycles, motorcycles and mopeds, constituted by a profiled element which is curved in a circular fashion and is symmetrical with respect to a centerline plane (P), said profiled element forming an outer annular seat ( 2 ) and an inner annular seat which are divided by an annular partition provided with slots arranged opposite the nipples ( 6 ) associated with the spokes of said rim, a tire of the tubeless type being associated with said outer annular seat so as to form a pressure chamber. The rim comprises closure elements that engage said slots in order to hermetically separate said outer annular seat from said inner annular seat.

BACKGROUND OF THE INVENTION

The present invention relates to a rim for mounting tubeless tires,particularly for bicycles, motorcycles and mopeds.

Rims for accommodating tires of the conventional type are already knownand are constituted by a profiled element which is curved in a circularfashion, is symmetrical with respect to a centerline plane, and forms anouter annular seat and an inner annular seat; the outer and innerannular seats are divided by an annular partition provided with slots.The outer annular seat is provided, on the side directed toward thecenter of the rim, with coupling holes through which slots guide nipplesfor connecting the spokes to the rim. The inner annular seat defineslateral shoulders, which form a receptacle for retaining the beads ofthe tire.

These rims have a severe drawback, which is due to the fact that theyonly allow mounting of conventional tires and therefore necessarilyentail interposing an inner tube between the receptacle and the tire;accordingly, such rims cannot be used as means for supportingtubeless-type tires.

Rims adapted for mounting tubeless tires are known from the documentsEP-A-0 709 141, Patent Abstracts of Japan vol. 2000, no. 06, 22 Sept.2000, and EP-A-0 615 865.

SUMMARY OF THE INVENTION

The aim of the present invention is to obviate the cited drawbacks byproviding a rim that does not suffer the above noted drawbacks.

Within this aim, an object of the present invention is to provide a rimthat can have usefulness and economical industrial application.

Still another object of the present invention is to provide a structurethat is simple, relatively easy to provide in practice, safe in use andeffective in operation.

This aim and these and other objects which will become better apparenthereinafter are achieved by a rim, according to the invention, which hasthe features set forth in the Claims.

Advantageous constructional features are set forth in the dependentclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages will become better apparent fromthe detailed description of a preferred non-exclusive embodiment of arim for mounting tubeless tires, particularly for bicycles, motorcyclesand mopeds, according to the invention, illustrated only by way ofnon-limitative example in the accompanying drawings, wherein:

FIG. 1 is a cross-sectional view of the rim according to the invention;

FIG. 2 is a cross-sectional view of said rim, on which a tire of thetubeless type is fitted hermetically;

FIGS. 3 and 4 are, respectively, an axial sectional view and a top viewof a sealing plug;

FIGS. 5 and 6 are views of a second embodiment of the plug of FIGS. 3and 4;

FIGS. 7 and 8 are respectively a side view and a sectional view of athird embodiment of the sealing plugs;

FIGS. 9 and 10 are sectional views of the sealing plugs of FIGS. 7 and 8respectively in a mounting position and in a mounted position;

FIGS. 11 and 12 are views of a fourth embodiment of the sealing plugs;

FIGS. 13 and 14 are views of a fifth embodiment of the sealing plugs;

FIGS. 15 and 16 are views of a sixth embodiment of the sealing plugs.

Similar or corresponding constructional features of the variousembodiments represented in the Figures are indicated therein by the samereference numerals.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the figures, the reference numeral 1 generallydesignates a bicycle wheel rim constituted by a profiled element, whichis curved in a circular fashion and is symmetrical with respect to acenterline plane P. The rim 1 has an outer annular seat 2 and an innerannular seat 3, which are separated by a partition 4. The outer annularseat 2 is provided with a plurality of receptacles 5, in which thenipples 6 connected to the ends 7 of a respective plurality of spokesare inserted. Two ridges 8 and 9 for stiffening the rim 1 are providedon the opposite side with respect to the plurality of receptacles 5, inorder to provide resistance to the mechanical stresses affecting the rim1. The partition 4 is interposed rigidly in a bridge-like fashionbetween the two ridges 8 and 9 and further stiffens the rim 1. Slots 10are provided in the partition 4, in opposition to each receptacle 5, inorder to allow access to the annular seat 2 and therefore allow thenipples 6 to be fixed in a fully automatic manner.

The inner annular seat 3 defines lateral flanges 11 suitable to retainthe beads 12 a of the tire 12, so that the association of said tire 12with the inner annular seat 3 forms a pressure chamber 13.

The slots 10 can be engaged removably and hermetically by closureelements constituted by sealing plugs 14, shown in FIGS. 3-6. Each oneof the sealing plugs 14 comprises a head 15 and a shank 16, betweenwhich sealing means 17 are formed in an annular fashion and engagehermetically the edge 10 a of the slot 10. The sealing means 17 isconstituted by an annular groove 18, which is delimited, in an upwardregion, by an expandable lip 19 associated with the head 15 and by anannular tooth 20 associated with the shank 16. The head 15 has, on itsupper face 21, mutually perpendicular recesses 22 shaped so as to allowthe compression of the head 15 toward the center, thus allowing easyinsertion/extraction of the sealing plug 15 in and from thecorresponding slots 10 and thus allowing separation hermetically, oncethe mounting of the tire 12 has been completed, of the pressure chamber13 from the outer annular seat 2.

In practical operation, the nipples 6 are guided through the slots 10and are fixed in the corresponding receptacles 5. After fixing thenipples and connecting the spokes to the rim by means of the nipples 6,the slots 10 are closed hermetically by means of the sealing plugs 14.This allows separation hermetically of the outer annular seat 2 from thepressure chamber 13 when the tubeless tire 12 is applied to the innerannular seat 3.

It has thus been found that the invention achieves the proposed aim andobjects.

In particular, the fact is stressed that a tubeless-type tire can bemounted on the above described rim.

Furthermore, it is very easy to assemble the spoke set, since thenipples and the corresponding spokes can be guided very easily throughthe plurality of receptacles.

The invention thus conceived is susceptible of numerous modificationsand variations, all of which are within the scope of the inventiveconcept.

A third embodiment is shown in the accompanying drawings 7 to 10.

In this third embodiment, the closure elements consist of sealing plugs23 having a frustum-like shape that forms a head 24 and a shank 25 whichcan expand and are provided with respective coaxially oppositecylindrical cavities 26 and 27. The head 24 comprises an annular groove28, which is delimited in an upward region by an expandable lip 29 andin a downward region by a tooth 30. The expandable lip 29 and the tooth30 form opposite abutments 29 a, 30 a which, by acting against the outerand inner edges of the slot 10, prevent the axial extraction of thesealing plug 23.

Complementary sealing plugs 31 are detachably associated with thesealing plug 23 and have a head 32 and a shank 33 on which expansionelements 38, constituted by frustum-shaped annular protrusions 39, areprovided. The complementary sealing plug 31 is inserted with its shank33 in the cylindrical cavity 26, which by way of the transverse pressureof the expansion elements 38 on the walls of said cavity 26 causes theexpansion of the head 24 and therefore a tighter seal of the sealingplug 23 on the slot 10.

Advantageously, as shown in FIG. 11, there are expansion elements 38formed by the frustum-shaped profile of the shank 33. In this case also,the result of the insertion of the complementary plug 31 in the sealingplug 23, by means of the frustum-shaped profile, is of the same typedescribed above.

In a fourth embodiment, FIGS. 11 and 12, the expansion elements 38 areconstituted by a threaded expandable insert 39, which is accommodatedsubstantially at the bottom of the cavity 26. In this case, thecomplementary plug 31 is screwed into the insert 39 through the cavity26, and said insert 39, by expanding against the walls of said cavity26, causes the head 24 to expand.

Conveniently, a fifth embodiment of the sealing plug 23 is providedwhich has a head 24 and a shank 25 having a cylindrical shape. Thesealing plug 23 is designed to removably enter the slot 10, whichprotrudes into the outer annular seat 2 by means of an undercut 40. Theinsertion and sealing of the sealing plug in the slot 10 are achieved byway of sealing means, which in this case consist of correspondinghelical threads 41, 42 provided respectively on the facing surfaces ofthe shank 25 and of the undercut 40. Furthermore, in order to increasethe seal and improve the hermetic separation between the outer annularseat 2 and the inner one 3, a ring 43 is interposed between the head andthe passage hole.

In a sixth embodiment, the closure elements consist of adhesive bands44, which are applied so as to provide a hermetic closure at the slots10. The adhesive bands 44 can be distributed with a constant spacing ateach slot 10 or continuously along the annular partition 4.

It has thus been shown that the invention achieves the proposed aim andobjects.

All the details may further be replaced with other technicallyequivalent ones.

In practice, the materials used, as well as the shapes and thedimensions, may be any according to requirements without therebyabandoning the scope of the protection of the appended claims.

The Italian Utility Model Applications No. BO2000U000139 andBO2001U000017 are the documents from which this application claimspriority.

1. A rim for mounting tubeless tires for bicycles, motorcycles andmopeds, constituted by a profiled element which is curved in a circularfashion and is symmetrical with respect to a centerline plane,comprising: an inner annular seat adapted to receive and retain atubeless type tire so as to form a pressure chamber; an outer annularseat provided with receptacles for nipples associated with spoke ends;an annular partition which divides said inner and outer seats and whichis provided with openings arranged opposite the nipples, said openingsbeing each provided with an edge surrounded by a pendent surface forminga respective undercut that protrudes into said outer annular seat; andclosure elements that engage in said openings in order to hermeticallyseparate said outer annular seat from said inner annular seat, saidclosure elements consisting of sealing plugs, each of which comprises acylindrical head and a shank that has a cylindrical surface with sealingmeans formed therebetween, said sealing means being constituted bycorresponding helical threads provided on the surface of said shank and,respectively, on the pendent surface forming said undercut, each one ofsaid sealing plugs being adapted to detachably engage in a respectiveone of said undercuts and hermetically close the respective opening byway of mutual engagement of said corresponding helical threads.
 2. A rimfor mounting tubeless tires for bicycles, motorcycles and mopeds,constituted by a profiled element which is curved in a circular fashionand is symmetrical with respect to a centerline plane, comprising: aninner annular seat adapted to receive and retain a tubeless type tire soas to form a pressure chamber; an outer annular seat provided withreceptacles for nipples associated with spoke ends; an annular partitionwhich divides said inner and outer seats and which is provided withopenings arranged opposite the nipples; closure elements that engagesaid openings in order to hermetically separate said outer annular seatfrom said inner annular seat which consists of sealing plugs, each ofwhich is adapted to detachably and hermetically engage in a respectiveone of said openings, and wherein said sealing plugs comprise each ahead and a shank with an annular groove formed therebetween that issuitable to engage hermetically an edge of a respective one of saidopenings and first and second coaxial and mutually opposite cavitiesformed therein, said shank having a frustum shape and said second cavityhaving an open end that faces said outer annular seat upon engagement ofthe sealing plugs in respective ones of said openings; and complementarysealing plugs each adapted to engage a respective sealing plug at a saidfirst cavity thereof.
 3. The rim of claim 1, wherein each of saidsealing plugs further comprises means for rotating said sealing plug toengage and disengage said corresponding helical threads.
 4. The rim ofclaim 1, further comprising a ring interposed between said head of eachof said sealing plugs and said openings.
 5. The rim of claim 1, whereinsaid shank of each of said sealing plugs is substantially coextensivewith said pendent surface forming said undercut when said helicalthreads of said sealing plugs fully engage said helical threads of saidpendent surface of said undercut.
 6. The rim of claim 1, wherein each ofsaid sealing plugs further comprises a shoulder disposed between saidhead and said shank, said shoulder contacting said annular partitionwhen said helical threads of said sealing plugs fully engage saidhelical threads of said pendent surface of said undercut.
 7. The rim ofclaim 2, wherein each of said sealing plugs further comprises anexpandable lip associated with said head and a tooth associated withsaid shank, said expandable lip and said tooth delimiting said annulargroove in an upward and, respectively, in a downward region thereof. 8.The rim of claim 2, wherein said complementary sealing plugs areprovided with a shank and with expansion elements that detachably engagein said first cavity so as to provide improved sealing action of saidplugs in said opening.
 9. The rim of claim 2, wherein said sealing plugshave a frustum-like shape, with a head and a shank that are expandable.10. The rim of claim 8, wherein said expansion elements are constitutedby a threaded expandable insert accommodated at a bottom part of saidfirst cavity, said complementary sealing plug being adapted to bescrewed with said shank inside said threaded expandable insert.
 11. Therim of claim 8, wherein said expansion elements are constituted byfrustum-shaped annular protrusions provided at said shank of saidcomplementary sealing plug.